Polyurethanes containing dispersed crystalline polyesters

ABSTRACT

A process is disclosed for producing resilient polyurethane foams by foaming an organic polyisocyanate, an iso-cyanate-reactive compound and a fusible polymer. The improvement in the hardness of the foams is achieved without adversely affecting the other properties of the foams, such as tensile strength and elongation.

This application claims the benefit of Provisional Application No.60/204,222, filed May 15, 2000.

The present invention is to a process for producing foams havingimproved load-bearing and resistance to humid aging without adverselyaffecting the other properties of the foam. In addition, the inventionis to a flexible foam produced by this process.

Flexible polyurethane foams are well-recognized articles of commerce.The flexible foams are generally characterized by the process used inproduction, either molded or free rise. Flexible foams having highresilience (HR) are characterized as having higher comfort or supportfactor and higher resilience than non-HR foams or conventional foam.Flexible foam is generally prepared by employing an isocyanate, a highequivalent weight polyol, water as the reactive blowing agent, andappropriate catalysts, cross-linkers and surfactants.

The load bearing of such foams is generally expressed in terms ofindentation force deflection (IFD) and/or compression force deflection(CFD). These measurements describe the ability of a foam to bear anapplied load, such as that of a person sitting on a foam cushion in achair or an automobile seat or lying on a mattress. Providing improvedload bearing offers several potential advantages. For example, betterload-bearing can permit one to obtain equivalent product performance atlower foam densities, thus reducing the amount of materials necessary toproduce the seat or the mattress.

There are several known technologies for improving foam load-bearing.For example, an organic and/or inorganic filler can be added into theformulation. However, this causes the foam's density to increase whileelongation at break and tear strength decrease substantially. Alsopoorer foam aging properties are obtained when fillers are used. Theequivalent weight of the polyol component can be reduced, however; thiscauses a loss of elongation and raises the glass transition temperatureof the polyurethane while detrimentally affecting foam resiliency.

U.S. Pat. No. 4,098,729 describe the use of high melting cross-linkerswith functionality higher than 2 to improve the hardness of the foam.

Moreover certain types of crystalline or semi-crystalline fillers havebeen tried to improve load bearing. U.S. Pat. No. 4,243,755 claims aprocess for the manufacture of reinforced polyurethane foams withfillers produced in situ and having particle size below 7 microns. U.S.Pat. No. 4,323,657 discloses finely, redispersible dispersions of highmelting polyhydroxyl compounds together with a process for theirpreparation. These polyhydroxyl compounds are stated to have a meltingpoint higher than the maximum temperature reached when producing thepolyurethane product made therefrom, hence these act as true fillers.

U.S. Pat. No. 4,302,551 relates to a process for preparing rigidcellular foam having urethane groups, isocyanaurate groups or both, withcertain polymer dispersions.

U.S. Pat. No. 4,560,708 claims the use of crystalline, ethylenicallyunsaturated polyesters as dispersed phase in a polyhydroxyl compound.These crystallite suspensions are preferably used to preparepolyurethane-group-containing polyisocyanurate polymers.

U.S. Pat. No. 4,435,537 is about storage stable dispersions comprisingcertain aromatic polyesters dispersed in certain polyhydroxyl compounds.Key to this technology is the melting viscosity at 150 deg C. of thepolyester which has to be between 15 and 3000 mPas.

Thus a new method of improving load-bearing of flexible polyurethanefoam while maintaining other important properties such as tensilestrength, tear strength, elongation, density, dry and humid compressionsets, resiliency and air flow within acceptable limits is desirable.Moreover, it would be desirable that technology for improvingload-bearing can be implemented using commonly available foamingequipment and under other processing conditions similar to thosecurrently used in making flexible polyurethane foams.

It has been surprisingly found that polyurethane foams having specificfusible polymers therein have increased load bearing (hardness) and aremore resistant to humid aging than foams produced in the absence of suchfusible polymers. These improved properties are obtained withoutadversely affecting the other properties of the foam.

In one aspect the invention is a process for the production of apolyurethane flexible product by reaction of a mixture of

(a) at least one organic polyisocyanate with

(b) at least one isocyanate-reactive composition comprising

-   -   (b1) from 50 to 99 percent by weight of at least one        isocyanate-reactive material having a functionality from 2 to 8        and a hydroxyl number of 20 to 140    -   (b2) from 1 to 50 percent by weight of an isocyanate reactive        fusible polymer substantially free of aromatic and having (1) a        melting point of between 45° C. and 180° C.; (2) a T_(g)/T_(m)        of less than 0.65, as measured in ° K; and (3) a calculated        composite interaction parameter (chi) of fusible polymer with        other polyurethane components of less than 2 at an absolute        temperature of 400° K or a chi of greater than 1.6 at 300° K,        wherein the weight percent is based on the total amount of (b)        and (b2)is either melted during the polyurethane production        process through internal exotherm of the polyurethane reactions        or is melted by external heating before or during the        polyurethane reactions and reacts with the polyisocyanate; or is        added dissolved in an appropriate solvent;

(c) optionally in the presence of a blowing agent and

(d) optionally additives or auxiliary agents known per se for theproduction of polyurethane foams.

In another aspect, this invention is a polyurethane product made as aresult of the above process which possess either a crystallinemicrostructure as evidenced by either TEM (Transmission ElectronMicroscopy), DMS (Dynamic Mechanical Spectroscopy) or DSC (DifferentialScanning Calorimetry).

In yet another aspect, this invention is a dispersion of micro-particlesof less than 100 microns of a fusible polymer (b2) dispersed in theisocyanate-reactive material (b1).

In yet another aspect, this invention is a dispersion of micro-particlesof less than 100 microns of a fusible polymer (b2) dispersed in thepolyisocyanate (a).

In a further aspect, this invention is an isocyanate terminatedprepolymer obtained by the reaction product of an excess of apolyisocyanate with a fusible polymer (b2) or a hydroxyl terminatedprepolymer obtained by reaction of the fusible polymer with polyol (b1)and isocyanate.

In still another aspect, this invention is a foam made from the processdisclosed herein.

Foams produced in accordance with the invention exhibit a number ofimportant advantages. In accordance with the present invention, it isreadily feasible to increase the hardness of polyurethane foams withouthaving to forgo other valuable foam characteristics, such as, theelasticity and resilience as well as the open cell nature of the foam.Further, relatively hard foams with relatively low unit weights can bemanufactured, or the hardness of any given foaming system can besignificantly increased without changing the unit weight or density.

In accordance with the present invention, a process for the productionof polyurethane products is provided, particularly for polyurethanefoams, using a fusible polymer. The use of a fusible polymer gives anincrease in foam hardness as determined by the CFD. This increasedhardness can be achieved with a decrease in the density of the foambelow 100 Kg/m³. In particular they have a foam density of less than 50Kg/m³. More preferred are foams that have a density of less than 40Kg/m³.

The increase in hardness will generally be 5 percent greater than a foamproduced in the absence of the fusible polymer. Preferably, the foam hasa hardness that is 10 percent greater than a foam produced in theabsence of a fusible polymer.

The foams produced with the fusible polymers of the present inventionalso have improved 75% humid aged compression sets (HACS) as measured byASTM D-3574-95.

The fusible polymer has a crystalline structure at room temperature andis preferably hydrophobic in its chemical composition. For instance ithas relatively long aliphatic chains.

The isocyanate which may be used with the present invention includealiphatic, cycloaliphatic, arylaliphatic aromatic isocyanates andmixtures thereof. Aromatic isocyanates, especially aromaticpolyisocyanates are preferred.

Examples of suitable aromatic isocyanates include the 4,4′-, 2,4′ and2,2′-isomers of diphenylmethane diisocyanate (MDI), blends thereof andpolymeric and monomeric MDI blends toluene-2,4- and 2,6-diisocyanates(TDI), m- and p-phenylenediisocyanate, chlorophenylene-2,4-diisocyanate,diphenylene-4,4′-diisocyanate, 4,4′-diisocyanate-3,3′-dimethyldiphenyl,3-methyldiphenyl-methane-4,4′-diisocyanate and diphenyletherdiisocyanateand 2,4,6-triisocyanatotoluene and 2,4,4′-triisocyanatodiphenylether.

Mixtures of isocyanates may be used, such as the commercially availablemixtures of 2,4- and 2,6-isomers of toluene diisocyanates. A crudepolyisocyanate may also be used in the practice of this invention, suchas crude toluene diisocyanate obtained by the phosgenation of a mixtureof toluene diamine or the crude diphenylmethane diisocyanate obtained bythe phosgenation of crude methylene diphenylamine. TDI/MDI blends mayalso be used. MDI or TDI based prepolymers can also be used, made eitherwith polyol (b1) or (b2), or any other polyol as described heretofore.Isocyanate-terminated prepolymers are prepared by reacting an excess ofpolyisocyanate with polyols, including aminated polyols orimines/enamines thereof, or polyamines.

Examples of aliphatic polyisocyanates include ethylene diisocyanate,1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane1,4-diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, saturatedanalogues of the above mentioned aromatic isocyanates and mixturesthereof.

For the production of flexible foams, the preferred polyisocyanates arethe toluene-2,4- and 2,6-diisocyanates or MDI or combinations of TDI/MDIor prepolymers made therefrom.

For flexible foam, the organic polyisocyanates and the isocyanatereactive compounds are reacted in such amounts that the isocyanateindex, defined as the number or equivalents of NCO groups divided by thetotal number of isocyanate reactive hydrogen atom equivalents multipliedby 100, ranges from 50 to 120 and preferably between 75 and 110.

The isocyanate-reactive materials (b1) for use in the present inventionhave an average of at least two isocyanate-reactive groups per molecule.Isocyanate-reactive compounds are well known in the art and includethose described herein and any other commercially available polyoland/or SAN, PIPA or PHD copolymer polyols with solids levels up to 50%.(PIPA is the reaction of olamine with polyisocyanate to producepolyaddition products, see U.S. Pat. No. 4,374,209. PHD stands forpolyharnstoffdispersion.) Such polyols are described in PolyurethaneHandbook, by G. Oertel, 2^(nd) edition, Hanser publishers. Mixtures ofone or more polyols and/or one or more copolymer polyols may also beused to produce polyurethane foams according to the present invention.

Representative polyols (b1) include polyether polyols, polyesterpolyols, polyhydroxy-terminated acetal resins, hydroxyl-terminatedamines and polyamines. The term “polyol” shall be used herein to refergenerally to these isocyanate-reactive compounds. Examples of these andother suitable isocyanate-reactive materials are described more fully inU.S. Pat. No. 4,394,491, the disclosure of which is incorporated hereinby reference. Alternative polyols that may be used include polyalkylenecarbonate-based polyols and polyphosphate-based polyols. Preferred arepolyols prepared by adding an alkylene oxide, such as ethylene oxide,propylene oxide, butylene oxide or a combination thereof, to aninitiator having from 2 to 8, preferably 2 to 6 active hydrogen atoms.Catalysis for this polymerization can be either anionic or cationic,with catalysts such as KOH, CsOH, Ba(OH)₂, boron trifluoride, or adouble cyanide complex (DMC) catalyst such as zinc hexacyanocobaltate.Unsaturation can be as low as 0.01 meq/g.

The polyol or blends thereof employed depends upon the end use of thepolyurethane product to be produced. The hydroxyl number and molecularweight of the polyol or polyols employed can vary accordingly over awide range. In general, the hydroxyl number of the polyols employed mayrange from about 20 to about 150.

In the production of flexible polyurethane foam, the polyol (b1) ispreferably a polyether polyol and/or a polyester polyol. The polyolgenerally has an average functionality ranging from 2 to 5, preferably 2to 4, and an average hydroxyl number ranging from 20 to 100 mg KOH/g,preferably from 20 to 70 mg KOH/g. As a further refinement, the specificfoam application will likewise influence the choice of base polyol. Asan example, for molded foam, the hydroxyl number of the base polyol maybe on the order of about 20 to about 60 with ethylene oxide (EO)capping, and for slabstock foams the hydroxyl number may be on the orderof about 25 to about 75 and is either all propylene oxide (PO), or mixedfeed EO/PO or is only slightly capped with EO. Both technologies use as(b1) blends of conventional polyols and/or copolymer polyols asdescribed heretofore.

The initiators for the production of polyols (b1) generally have 2 to 8functional groups that will react with the polyol. Examples of suitableinitiator molecules are water, organic dicarboxylic acids, such assuccinic acid, adipic acid, phthalic acid and terephthalic acid andpolyhydric, in particular dihydric to octahydric alcohols or dialkyleneglycols, for example ethanediol, 1,2- and 1,3-propanefdiol, diethyleneglycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol,trimethylolpropane, pentaerythritol, sorbitol and sucrose or blendsthereof. Other initiators include compounds linear and cyclic compoundscontaining a tertiary amine such as ethanoldiamine,N-methyldiethanolamine, triethanoldiamine, ethylene amines and variousisomers of toluene diamine.

Polyol (b1) can contain BHT or any other proper antioxidants and haveunsaturation (monol level) which can be as low as 0.01 meq/g.

The fusible polymers (b2) used in the present invention are solid,crystalline and preferably hydrophobic polyester polyols that undergo aphase transition between 45 and 180° C. Phase transition means a changein a property such as melting point (Tm). Preferably the fusiblepolymers undergo a phase transition between 45 and 140° C. Morepreferred are fusible polymers which undergo a phase transition between50 and 120° C. The Tm can be measured by standard techniques in the art,such as differential scanning calorimetry.

Generally the fusible polymers are polyester polyols with an averagehydroxyl equivalent weight from 250 to 10,000. Preferably the equivalentweight is between 500 and 8,000. Functionality of fusible polymer (b2)is from 2 to 8, more preferably from 2 to 4 and most preferably 2, toget optimal crystallization.

Processes for producing fusible polymers of the present invention aredescribed in “Polyurethane Handbook” by G. Oertel, Hanser Publisher andinclude polycondensation of multifunctional carboxylic acids andhydroxyl compounds, polycondensation of hydroxy-carboxylic acids, thepolymerization of ring esters (lactones) and the polyaddition ofpolycarboxylic anhydride with epoxides as well as in the reaction ofacid chlorides with the alkali salts of hydroxyl compounds.Transesterification is also possible with hydroxyl as well as withcarboxyl compounds.

Preferred fusible polymers for use in the present invention are derivedfrom a ring opening polymerization process between a lactone and aninitiator capable of initiating the ring opening. Other preferredfusible polyols can also be derived from the condensation polymerizationof omega hydroxy acids or esters using a similar initiator as thatdescribed for lactone polymerization. Such lactones, esters and acids,which make up the repeating unit of the polyester, have 7 to 20 carbonatoms in the ring or in the chain. Preferred are lactones, esters andacids having 8 to 18 carbon atoms in the ring or in the chain. Morepreferred are lactones, esters and acids having 9 to 16 carbon atoms inthe ring or in the chain. Most preferred are lactones, esters and acidshaving 11 to 16 carbon atoms in the ring or chain. The carbons of thelactone, esters and acids may be substituted with an alkyl, cycloalkyl,alkoxy and single ring aromatic hydrocarbon radicals. When the carbonatoms of the ring or chain contain such substituents, it is preferredthat the total number of carbon atoms in the substituents on a lactonering or chain does not exceed about 20.

Initiators that are suitable for producing such fusible polymers arecompounds having 2 to 8 reactive sites, capable with or without the aidof a catalyst, of opening the lactone ring. Such reactive sites includehydroxyl, primary or secondary amine or thiol groups. Compounds havingat least two hydroxyl groups per molecule are preferred. Preferred areinitiators having 2 to 4 hydroxyl groups.

To increase the rate of the ring opening, various catalysts can be used.Such catalysts are known in the art and include basic and neutral, aswell as acidic, ester interchange catalysts, including Group IItransition metal base catalysts. Such catalysts are generally used in anamount form 0.001 percent to 0.5 percent by weight of the total reactionmixtures.

Reaction conditions to initiate and continue the polymerization of thelactone, esters and acids are known to those skilled in the art. Forexample, see U.S. Pat. Nos. 2,933,477 and 2,933,478, the disclosures ofwhich are incorporated herein by reference.

Another example of fusible polymers (b2) are those produced fromdicarboxylic acids, preferably aliphatic dicarboxylic acids, having 2 to20 carbon atoms, preferably 6 to 15 carbon atoms, in the alkyleneradical and multifunctional alcohols, preferably diols, having from 2 to20 carbon atoms, preferably diols having 6 to 15 carbon atoms.Preferably the diacid is substantially free of any ethyleneicallyunsaturated groups (i.e., carbon-carbon double bonds). These acidsinclude, for example, aliphatic dicarboxylic acids such as glutaricacid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, undecanediolic acid, dodecanedioic acid andcycloaliphatic dicarboxylic acids such as 1,3- and 1,4-cyclohexanedicarboyxlic acid. In general, aromatic dicarboxylic acids are notsuitable as the melting point is too high, greater than 180° C. when anequivalent weight of 1000. Examples of di- and multifunctional alcoholsare ethylene glycol, diethylene glycol, triethylene glycol, propyleneglycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol,1,4-butanediol and 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol,1,12-dodecanediol, glycerine, neopentyl glycol, trimethylpropane.

Preferably, these polyesters, prepared by polycondensation ofmultifunctional carboxylic acids and hydroxyl compounds, are made from adiacid and a diol such that the repeating unit of acid+alcohol has intotal at least 9 carbons atoms. More preferably these have a total of 10to 30 carbon atoms.

The process for making such polyester polyols are well known to those inthe art. See Polyurethane Handbook, by G. Oertel, 2^(nd) edition, Hanserpublishers. An example of such polyester polyols available commerciallyis a polyol, having a molecular weight of about 3500 and a melting pointof 65° C. sold by Degussa-Huls AG under the trademark DYNACOL 7381 andother related products as described in the technical leaflet: Dynacoll7000, The Building Block System for Moisture Curable Hot Melt Adhesivesand Sealants. Preferred products are the Dynacoll 7300 series which arepartially crystalline solids. Similar compounds from other suppliers canalso be used with this invention.

Fusible polymers (b2) also include polyester polyols produced by thepolyaddition of a polycarbonate anhydride with epoxides. Such a processproduced copolymers with alternating units obtained from the carboxylicanhydride and the epoxide. In general, the epoxide has 2 to 4 carbonatoms and the polycarbonate anhydride from 7 to 20 carbon atoms. Processfor producing the starting monomers is given in J. Am. Chem. Soc. 85,654 (1936).

Fusible polymers (b2) may also be produced by transesterification of apolyester with an alcohol having at least 2 hydroxyl groups. Preferredare alcohols having 2 to 4 hydroxyl groups. The process for producingsuch polymers are known in the art, see Polyurethane Handbook, by G.Oertel, 2^(nd) edition, Hanser publishers.

Fusible polymer (b2) can be combined with stabilizers, especiallyproducts which prevent or slow down hydrolysis. An example of suchproducts are Stabapol* additives, available from Rhein Chemie RheinauGMBH.

The components to produce the fusible polymers (b2) of the presentinvention are selected to produce compounds having the hydroxylequivalent weight and hydroxyl numbers to give a melting point or Tmwithin the desired range stated above. The effect and activity of thefusible polymers is that the foaming system, in the course of thefoaming and while there are still unreacted isocyanates left in thereactants, reaches a temperature that is above the melting temperatureor Tm of the fusible polymer. In instances where the temperature of thefoamed reaction mixture does not reach the melting temperature or Tm ofthe added fusible polymer, extraneous heat may be added to the system,or the fusible polymer can be blended in melted form with the otherreactants.

The amount of fusible polymer (b2) used is generally from 1 to 50 weightpercent of the total polyol composition (b). Preferably the amount offusible polymer is present from 2 to 40 weight percent of (b). Morepreferably the amount of fusible polymer is present from 2 to 30 weightpercent of (b). Most preferred is that from 2 to 20 weight percent of(b) is a fusible polymer (b2).

While not wishing to be bound by any theory of mode of action, it isbelieved that four main criteria are defining the fusible polymers thatgive the desired increase in foam load-bearing or elastomer E-modulus.First, the fusible polymer must have a crystalline melting temperatureTm which is (a) low enough to allow it to melt within the temperaturewindow of fabrication, and (b) is high enough that once itrecrystallizes and is incorporated into the foam or elastomer it doesnot melt but remain solid over the most common use temperature range ofthe fabricated article. This melting temperature range is from 45 to180° C. Preferably the melting temperature range is 50 to 150° C.

Second, the fusible polymer must have a low ratio Tg/Tm, as expressed inabsolute temperature units, to get the optimum “intrinsiccrystallizability”, a ratio of less than 0.75 is preferred, morepreferably of less than 0.70, and most preferred is 0.65 or less.

Third, the fusible polymer must have a low “composite interactionparameter” (chi) with the mixture of the other formulation ingredientsat elevated temperatures, hence above Tm, in order to have good“relative miscibility” when melted in order to disperse in these othercomponents and be able to react with isocyanate. This (chi) compositeshould preferably be less than 2, more preferably less than 1.5 attemperature of 400° K.

Fourth, the fusible has a calculated chi value at 300° K is preferablyhigher than 1.6 to get phase separation upon cooling.

“Chi” values are unitless values which are conveniently calculated usingCerius², version 3 or higher software products of Molecular Simulations,Inc. Details on the calculation procedures are described in K. Choi andW. H. Jo, Macromolecules 30:1509-1514 (1997), the disclosure of which isincorporated herein by reference. Decreasing chi values predictimproving relative miscibility. Good relative miscibility is predictedwhen the calculated chi value is 1.0 or below. Preferably, chi valuesfor the high-melting polymer and organic polyisocyanate and/or theisocyanate-reactive component used in the highest concentration aredeveloped. More preferably, chi values are developed for both thehigh-melting polymer and organic polyisocyanate and theisocyanate-reactive component used in the highest concentration. Inaddition, it is preferred to develop chi values over the temperaturerange that will be encountered during the processing of the formulation,that is, from about 300K to about 473K, more preferably from about 350Kto about 453K. It should be noted that the molecular weight of thefusible polymer can be adjusted to meet these physical requirements.

The chi values given above are calculated to normalize to a 3,000molecular weight of the high-melting or amorphous polymer. The samemiscibility thresholds can also be used to identify other preferredembodiments of this invention at different molecular weights by usingthe value of (chi×MW)/3000 rather in place of the value chi itself asthe basis of comparison if the molecular weights differs from 3,000. Thevalues also use the assumption that the high-melting of amorphouspolymer constitutes a volume fraction of about 0.1 of the totalformulation and the polyurethane or polyurethane/urea hard segmentweight fraction is about 0.3. It should be noted that the molecularweight of the fusible polymer can be adjusted to meet these physicalrequirements.

The fusible polymers of the present invention may be introduced into thefoaming system in such a manner that the fusible polymers are dispersedin the polyol (b1) having active hydrogen atoms. The fusible polymersmay also be directly added to the batch or system to be foamed in a finedistribution. In a preferred embodiment, the fusible polymer isintroduced in the form of a dispersion in the polyol (b1).

It is important that the fusible polymer (b2) is dispersed as fineparticles below 35 microns in polyol (b1), more preferably below 10microns, and even more preferably below 3 microns when used tomanufacture flexible foams. This allows a faster melting of (b2) duringthe foaming reactions and a better distribution of the isocyanatereacted fusible polymer in the final polyurethane matrix. It has beenfound that out of several ways to disperse the fusible polymer (b2) in(b1), the best procedure to get very fine particles of (b2) in (b1) isto pour or inject under strong stirring conditions melted (b2) in coldpolyol (b1), cold meaning room temperature or temperature not higherthan 40 deg C. Polyol (b1) Can be used by itself or can be preblendedwith the other components of the polyol formulation before adding themelted polymer (b2). Seed and/or stabilizer can be added to (b1) priorto pouring melted polymer (b2). In that case it could also be possibleto heat (b1) and (b2) together until the melting point of (b2) isreached and then to cool everything under stirring. Another possible wayto get fine particles is to inject in melted form the fusible polymer(b2) directly in the foaming machine mix-head and hence to disperse itinstantaneously in the blend polyol (b1), water, catalysts, surfactantsand other additives. Preferably this injection is done before the wholecomponent system is put in contact with the isocyanate. Another optionis the injection of melted polymer (b2) in the isocyanate stream of themachine mix-head, hence polymer (b2) can be reacted before beingdispersed in the polyol blend. A fourth method consists in micronizingthe particles of fusible polymer (b2) at room temperature and in addingproper anti-caking, wetting and/or stabilizer agents. Then this powder(b2) can be dispersed at room temperature under stirring in polyol (b1).Usually the temperature reached during this dispersion process, due tostirring, does not reach the melting point of polymer (b2). Finallyanother option is to dissolve the polymer in a proper solvent which willevaporate under the reaction exotherm and let the polymer precipitateand react in the polyurethane components. An example of such a solventis methylene chloride.

All of these possibilities can be practiced with prepolymers made bypre-reacting polymer (b2) with an isocyanate or by reacting (b2) withthe isocyanate in presence of (b1) under stirring. It is also feasibleto transesterify (b2) in (b1) using proper catalysis, or even to produce(b2) in situ in the polyol (b1).

It is desirable that the reaction product between the fusible polymer(b2) and the isocyanate used to make the polyurethane foam is not toocompatible with the rest of the foam components so as to separate andcrystallize or re-solidify as a distinctive phase upon subsequent foamcuring and cooling.

Polyurethane curing and cooling can be adjusted to optimize thiscrystallization or solidification. For instance, force cooling asdescribed in U.S. Pat. No. 3,890,414 can be practiced with slabstockfoams to speed up the cooling of the block and to get more uniformtemperature upon curing. On another hand, with molded foams, which havemuch larger surface to volume ratio than slabstock foams, a post-curingat demold may improve the annealing of the crystallized or solidifiedpolymer. In general, it is thought that rapid cooling is beneficial,provided the polymer (b2) has had time to react with isocyanate uponmelting.

A seed may be added to the polyurethane reactants to organize and speedup the crystallization or solidification of the isocyanate reactedpolymer (b2) in the polymer. For instance, the SAN particles of thecopolymer polyol can be considered as acting as such a seed. Other seedscan be organic and/or inorganic compounds which are solid at roomtemperature. Catalysts as described in U.S. Pat. No. 5,489,618, in E.P.1,018,525 and in E.P. 1,018,526 are of interest for the presenttechnology.

Depending on the viscosity of the polyol to be foamed, dispersions maybe formed whose viscosities might be too high for practical use. In suchinstances, it is feasible to use polyols or polyether monols with alower viscosity as dispersion media. In doing so, it must be consideredthat the introduction of polyether monols into the foamed polyurethanefoams causes a softening effect.

For producing a polyurethane-based foam, a blowing agent is generallyrequired. In the production of flexible polyurethane foams, water ispreferred as a blowing agent. The amount of water is preferably in therange of from 0.5 to 10 parts by weight, more preferably from 2 to 7parts by weight based on 100 parts by weight of the polyol. Carboxylicacids or salts are also used as blowing agents. It is clear that thewater level in the foam formulation by reacting with isocyanateinfluences the overall exotherm of the foaming mass and that the highestthe water level in the foam formulation, the higher and the faster theexotherm is. Hence higher water containing formulation will melt morereadily the fusible polymer (b2).

While not preferred for flexible foams, hydrocarbon blowing agents canbe used to augment the blowing agent. Hydrocarbons are volatile C₁ to C₅hydrocarbons. The use of hydrocarbons is known in the art as disclosedin EP 421 269 and EP 695 322, the disclosures of which are incorporatedherein by reference. Preferred hydrocarbon blowing agents are butane andisomers thereof, pentane and isomers thereof (including cyclopentane),and combinations thereof. Also possible is the use of liquid or gaseouscarbon dioxide as auxiliary blowing agent.

When a hydrocarbon, hydrochlorofluorocarbon, or the hydrofluorocarbon isused as a blowing agent, the amount is generally not more than 40 partsby weight of component (b) and preferably not more than 30 parts byweight of component (b). Water and a combination of hydrocarbon,hydrochlorofluorocarbon, or the hydrofluorocarbon may also be used ablowing agent.

In addition to the foregoing critical components, it is often desirableto employ certain other ingredients in preparing polyurethane polymers.Among these additional ingredients are surfactants, preservatives, flameretardants, colorants, antioxidants, reinforcing agents, stabilizers andfillers.

In making polyurethane foam, it is generally preferred to employ anamount of a surfactant to stabilize the foaming reaction mixture untilit cures. Such surfactants advantageously comprise a liquid or solidorganosilicone surfactant. Other surfactants include polyethylene glycolethers of long-chain alcohols, tertiary amine or alkanolamine salts oflong-chain alkyl acid sulfate esters, alkyl sulfonic esters and alkylarylsulfonic acids. Such surfactants are employed in amounts sufficientto stabilize the foaming reaction mixture against collapse and theformation of large, uneven cells. Typically, 0.2 to 3 parts of thesurfactant per 100 parts by weight total polyol (b) are sufficient forthis purpose.

One or more catalysts for the reaction of the polyol (and water, ifpresent) with the polyisocyanate can be used. Any suitable urethanecatalyst may be used, including tertiary amine compounds, amines withisocyanate reactive groups and organometallic compounds. Exemplarytertiary amine compounds include triethylenediamine, N-methylmorpholine,N,N-dimethylcyclohexylamine, penta-methyldiethylenetriamine,tetramethylethylenediamine, bis (dimethylaminoethyl) ether,1-methyl-4-dimethylaminoethyl-piperazine,3-methoxy-N-dimethylpropyl-amine, N-ethylmorpholine,dimethylethanolamine, N-cocomorpholine, N,N-dimethyl-N′,N′-dimethylisopropylpropylenediamine, N,N-diethyl-3-diethylamino-propylamine anddimethylbenzylamine. Salts of such amines can also be used as delayedaction catalysts. Exemplary organometallic catalysts includeorganomercury, organolead, organoferric and organotin catalysts, withorganotin catalysts being preferred among these. Suitable tin catalystsinclude stannous chloride, tin salts of carboxylic acids such asdibutyltin di-laurate, as well as other organometallic compounds such asare disclosed in U.S. Pat. No. 2,846,408. A catalyst for thetrimerization of polyisocyanates, resulting in a polyisocyanurate, suchas an alkali metal alkoxide may also optionally be employed herein. Theamount of amine catalysts can vary from 0.02 to 5 percent in theformulation or organometallic catalysts from 0.001 to 1 percent in theformulation can be used. Autocatalytic polyols, based on amineinitiators containing tertiary amine groups, can also be used to speedup the foaming or curing reactions.

A crosslinking agent or a chain extender may be added, if necessary. Thecrosslinking agent or the chain extender includes low-molecularpolyhydric alcohols such as ethylene glycol, diethylene glycol,1,4-butanediol, and glycerin; low-molecular amine polyol such asdiethanolamine and triethanolamine; polyamines such as ethylene diamine,xylenediamine, and methylene-bis(o-chloroaniline). The use of suchcrosslinking agents or chain extenders is known in the art as disclosedin U.S. Pat. Nos. 4,863,979 and 4,963,399 and EP 549,120, the disclosureof which are incorporated herein by reference.

The applications for foams produced by the present invention are thoseknown in the industry. Flexible foams find use in applications such asfurniture, such as furniture cushions and mattresses or other beddingapplications, and transportation vehicle seating, such as, automobileseats, two wheeled vehicles (motorized or not), watercraft, snowmobiles,all-terrain vehicles, aircraft and the like, sun visors, steeringwheels, armrests, door panels, noise insulation parts and dashboards.The increase in hardness obtained pursuant to the present invention isof particular interest for foam systems which are marketed under thenames of high resilient (HR) or cold foam, which is characterized byhigh resiliency measured according to ASTM D 3574-95 with values of atleast 50 percent.

Processes for producing polyurethane products are well known in the art.In general components of the polyurethane-forming reaction mixture maybe mixed together in any convenient manner, for example by using any ofthe mixing equipment described in the prior art for the purpose such asdescribed in Polyurethane Handbook, by G. Oertel, Hanser publisher.

The polyurethane products are either produced continuously ordiscontinuously, by injection, pouring, spraying, casting, calendering,etc; these are made under free rise or molded conditions, with orwithout release agents, in-mold coating, or any inserts or skin put inthe mold. In case of flexible foams, those can be mono- ordual-hardness.

When molding, the tool has to be maintained at the temperature givingbest processing and fast curing. For instance, in case of flexiblefoams, the mold has to be kept at a temperature between 35 and 90° C.,more preferably between 45 and 70° C. For Hot Cure molding, the mold is,after foam pouring, heated to temperatures between 150 and 200° C.Temperatures which are commonly attained in the core of slabstock foambuns are between 120 and 170° C.

The preparation of the polyurethane foams may be effected in closedmolds or as free rise or as slabstock foam. When the foaming is carriedout in molds, the reaction mixture to be foamed is inserted into a moldof metal or plastic. Generally, the amount of foamable reaction mixtureto be foamed is inserted will be such that the mold is just filled.However, it is feasible to use larger amounts of foamable mixture. Inproducing slabstock foam in open vessels, the mixture to be foamed isinserted into a stationary open mold or onto a conveyor belt that isgenerally lined and the foam is allowed to rise. Proper square blockprocesses can also be used to eliminate the top crown of the bun. Thefinish-foamed mold or slab foam bodies may subsequently be subjected toan after treatment as already discussed.

The following examples are given to illustrate the invention and shouldnot be interpreted as limiting in anyway. Unless stated otherwise, allparts and percentages are given by weight.

A description of the raw materials used in the examples is as follows.

SPECFLEX ™ is a glycerine/sorbitol initiated propylene oxide NC 632polymer capped with ethylene oxide available under the TradenameSPECFLEX from The Dow Chemical Company. The average hydroxyl number is32, average equivalent weight is about 1726 and the functionality isbetween 4 and 5. VORANOL is a glycerine initiated propylene oxidepolymer CP 4702 capped with ethylene oxide available under the trademarkVORANOL from the Dow Chemical Company. The average hydroxyl number is35. VORANOL is a glycerine propylene oxide polymer available under 3040the trademark VORANOL from the Dow Chemical Company. The averagehydroxyl number is 56. VORANOL is a 1,000 diol, capped with EO,available from the EP-2001 Dow Chemical Company. VORANOL is a 1,000diol, made from propylene oxide, available P-1010 from The Dow ChemicalCompany. VORANOL is a 6,000 MW polyol initiated with glycerine and CP6008 ethylene-oxide capped, available from The Dow Chemical Company.VORANOL ™ is a glycerine initiated polyol obtained by a mixed feed CP1421 of ethylene oxide/propylene oxide using 75% ethylene oxide,available from The Dow Chemical Company under the Tradename VORANOL. Thepolyol has an average equivalent weight of about 1675 and an averagehydroxyl number of 33. VORANOL is a sorbitol initiated polyol availablefrom 4053 The Dow Chemical Company. SPECFLEX ™ is a 40% SAN basedcopolymer polyol with an average NC 700 hydroxyl number of 20 availablefrom The Dow Chemical Company. VORALUX is a 40% SAN based copolymerpolyol, with an HL 400 average hydroxyl number of 20 available from TheDow Chemical Company. DEOA is dliethanolamine. 1,4-BDO is1,4-Butanediol. NIAX ™ is a proprietary delayed action amine catalystA-300 available from CK-Witco-OSI Specialties. NIAX ™ is a proprietarydelayed action amine catalyst A-400 available from CK-Witco-OSISpecialties. NIAX A-1 is an amine catalyst available from CK-Witco-OSISpecialties. DABCO ™ is a triethylene diamine catalyst available as a 3333 LV percent solution in dipropylene glycol available from Air Productsand Chemicals Inc. DABCO T-9 is a Tin based catalyst available from AirProducts and Chemicals Inc. TEGO- is a silicone based surfactantobtained from Th. STAB ™ Goldschmidt Ag. B 8708 TEGOSTAB is a siliconebased surfactant obtained from Th. BF 2370 Goldschmidt AG. TEGOSTAB is asilicone based surfactant obtained from Th. B 8681 Goldschmidt AG.DABCO ™ is a silicone surfactant obtained from Air Products DC 5164 andChemicals Inc. FOMREZ is a Tin based catalyst available from Witco UL-32VORA- is an 80/20 blend of 2,4/2,6 isomers of Toluene NATE ™diisocyanate available from The Dow Chemical T-80 Company under theTradename VORANATE. ISONATE is 4,4′-Methyldiphenylisocyanate availablefrom The M-125 Dow Chemical Company under the trademark ISONATE.SPECFLEX is a MDI/PMDI blend available from The Dow NE-112 ChemicalCompany. PPDL2 is a polypentadecalactone polyester based polymerprepared from pentadecalactone and a diol initiator, the preparation ofwhich is described herein. PPDL2 has a Tm of about 92C., a Tg/Tm (° K.)of 0.573 and a calculated chi in a PPDL2/polyol/TDI blend of 3.72 at300° K. and 1.62 at 400° K. PPDL3 is a polypentadecalactone polyesterbased polymer made with a triol initiator, the preparation of which isdescribed herein. PUDL2 is a polyundecalactone (prepared via11-hydroxyundecylenic acid methyl ester) polyester-based polymer madewith a diol initiator, the preparation of which is described herein.PUDL3 is a polyundecalactone prepared via 11-hydroxyundecylenic acidmethyl ester) polyester-based polymer made with a triol initiator, thepreparation of which is described herein. SEED A is an 8% SAN basedcopolymer polyol made with Voranol CP 4702 polyol and with particle sizebelow one micron. STABILI- is a 8% Lauryl methacrylate based ZER Apolymer in Voranol CP 4702 polyol modified according to EP 162,589STABILI- is a 8% Butyl acrylate based polymer in Voranol ZER B CP-4702polyol modified according to EP 162,589 DYNACOLL is a polyester polyolwith a melting 7360 point of 55° C. available from Degussa-Huels.Dynacoll 7360 has a Tg/Tm of 0.624 and a calculated chi composite ofDynacoll 7360/polyol/TDI blend of 2.08 at 300° K and 0.87 at 400° K.DYNACOLL is a polyester polyol with a 7380 melting point of 70° C.available from Degussa Huels. Dynacoll 7380 has a Tg/Tm of 0.62 and acalculated chi composite of Dynacoll 7380/polyol/TDI blend of 2.79 at300° K. and 0.89 at 400° K. DYNACOLL is a polyester polyol with amelting point 7381 of 65° C. available from Degussa-Huels. Dynacoll 7381has a Tg/Tm of 0.655 and a calculated chi composite of Dynacoll7381/polyol/TDI blend of 1.88 at 300° K. and 0.89 at 400° K. PCL is apolycaprolactone polymer based on a diol initiator with 2,000 MWavailable from Aldrich. This product has a softening point of 50° C. PCLhas a Tg/Tm of 0.655 and a calculated chi composite of PCL/polyol/TDIblend of 1.51 at 300° K. and 0.67 at 400° K.General experimental conditions were as follows.

Preparation of PPDL2. Pentadecalactone, PDL (100 g) and 1,6-hexane diol(6.0 g) in a 10:1 molar ratio are added to a vessel and heated to 150°C. under a nitrogen atmosphere with mixing. Tin(II)-2-ethyl hexanoate(0.5 g), a catalyst, is added and the temperature of the reaction israised to 190° C. The progress of the polymerization is monitored byobserving the disappearance of the PDL. When the polymerization iscomplete, the resulting hot polymer melt is poured into 700 mL ofanhydrous toluene. The resulting solution is cooled to allow the polymerto precipitate. The resulting precipitate is isolated by filtration,washed with hexane and dried in a vacuum oven at room temperature toconstant weight. The resulting polyester diol is isolated as a whitecrystalline solid having a Tg of −50° C. and Tm 89° C. A number averagemolecular weight of 2,770 was obtained as measured by MALDI-TOF massspectroscopy.

Preparation of PPDL3. The preparation of PPDL3 is carried out in asimilar manner as for PPDL2 except that 10.3 g of trimethylol propane(TMP) is used as the initiator and 150 grams of PDL is used. The polyolwas recrystallized from 1 L of toluene to give 132 g of thepolypentadecalactone triol. The measured Tm is 82.3° C.

General preparation for PUDL2 and PDDL2. The procedures for thepreparation of both PUDL2 and PDDL 2 are the identical and we shalldescribe the preparation of PUDL2 in this example. This procedure issimilar to that described for the preparation of PPDL2 except thatmethanol is removed during the coarse of the polymerization. The removalof methanol is further facilitated by the use of a vacuum towards thelatter stages of the reaction. The desired vacuum is determined to suchthat only the methanol of condensation is removed along with residualtraced of unreacted materials at the reaction temperature.

General preparation for PUDL 3 and PDDL3. The procedure is essentiallythe same as that described above for PPDL3, PUDL2 and PDDL2.

General Foam Formulation HR Molded and Free Rise Foams

In addition to the components listed in the working examples, the basicfoam formulation used for HR foams contained the following components,in percent by weight of the polyol and/or polyol blend.

Formulation A Formulation B Voranol CP 4702 0 39 Water 3.7 3.7 DEOA 1.01.0 NIAX A-300 0.25 (contains 50% water) 0 NIAX A-400 0.1 (contains 30%water) 0 Niax A-1 0 0.08 DABCO 33 LV 0.3 0.50 TEGOSTAB B 8708 0.80 0.80DABCO DC 5164 0.20 0.20Bench and Machine Molded and Free Rise Foams

For examples 1-4 containing the PPDL-2 polymer, the PPDL was added tothe NC 632 polyol, water, catalyst, silicone premix as a fine powder,then dispersed under stirring at 3,000 RPM for 30 s, before adding theisocyanate, stirring for another 5 s and pouring the reactants in acardboard box in case of free rise foam, or in a 30×30×10 mm aluminummold heated at 60 deg C. which was subsequently closed, in case ofmolding. For examples 5-7, the PPDL-2-NC 632 blend was heated to 100°C., hence above the melting point the PPDL-2 and the mixture was leftcooling down to room temperature under high shear stirring at about5,000 RPM. This process gave a fine dispersion of the PPDL in the NC632polyol which has been measured to be around 35 microns. For examples14-16 the PPDL and/or the Dynacoll's were melted at 100 deg C., thenpoured under stirring in the polyol, water, amine, surfactant premixmaintained at room temperature, just prior to adding the isocyanate.This gave particle sizes which have been measured to be less than 10microns. The release agent used for the molded foam was Klueber 41-2013available from Klueber Chemie.

Machine Molded Foams

Machine molded foams were produced using a high-pressure impingement mixhead. The mold temperatures was 60° C., polyol temperature 35° C. andthe isocyanate temperature 20° C. The polyol recirculation pressure(bar) was 160 and the isocyanate recirculation pressure was 150 bar. Thetotal output from the mix head into the mold is between 210-236 g/sdepending on the formulation used. Mold size is 40×40×10 cm with a metalinsert, hence with a total volume of 15.75 liters.

Slabstock Foams

Slabstock foams were produced using a Polymech machine equipped withhigh pressure mix-head and hydraulic stirrer. All raw materials wereused at a temperature of 21 deg C. Polyol output was 20 kg/min at 3 barspressure while other components were injected at pressures between 20and 40 bars in the mix-head. Conveyor speed was 3.2 m/min and blockwidth was 0.80 m.

General Foam Formulation Conventional Slabstock Foam

In addition to the components listed in the working examples, the basicformulation used for conventional (non HR) slabstock foams contained thefollowing components in percent by weight of the polyol and/or polyolblend:

Water 4.0 Niax A-1 0.04 Dabco 33LV 0.12 Dabco T-9 0.18 Tegostab BF 23700.80 Voranate T-80 (Index 110)Test Procedures

Density is measured according to ISO 845-95 and is expressed in kg/m3.Airflow is measured by test method ASTM D3574-95 and reported in cubicfeet/min (cfm). IFD is indention force deflection as measured by ISO2439-97 and is reported in Newton at 40% foam deflection. CFD iscompression force deflection as measured by Peugeot D-41-1003-86 testmethod and is reported as kilo pascals under 25%; 50% and 65%deflections. CS is dry compression set as measured by PeugeotD-45.1046-83 test method (70% CD) and is reported as percent. 75% Cs isdry compression set as measured according to ISO 1856-80. Elongation ismeasured by Peugeot D-41.1050.85 test method and is reported in percent.Tensile strength is measured by Peugeot D-41.1050.85 test method and isreported in kilo pascals. Tear strength is measured by PeugeotD-41.1048-81 test method and is reported in Newton/meter. Resiliency ismeasured by ASTM 3574-95 test method and is reported in percent. HACS isa humid aging compression set test as measured by ASTM D3574-95 (75% CD)and is reported as percent. Dynamic fatigue is carried out according toPeugeot D-42.1047/B97 test method. Both height loss and load loss arereported in percent.

EXAMPLES 1 TO 4

Bench scale tests were done to determine the effect of replacing part ofa high functional polyol in a flexible foam formulation with PPDL2. Thefoam formulations and the properties of the resulting molded and freerise foam are given in Tables 1, 2 and 3 respectively.

TABLE 1 INITIAL BENCH SCALE STUDY ON MOLDED AND FREE RISE FOAM FoamNumber Ref A 1 2 3 4 NC 632 80 75 70 65 60 NC 700 20 20 20 20 20 PPDL2powder 0 5 10 15 20 T-80 44.8 44.8 44.8 44.8 44.8 Index 100 100 100 10099 Demold time 4 4 4 5 5 (min) Mold fill time 43 44 44 47 49 (s) (Partweight) 333 332 340 338 336 Molded density 37 37 37.8 37.6 37.3Temperature at 70 68 69 67 73 mold fill (C.) Time to reach 80 87 87 8788 90 deg C. (s) Demold 133 130 129 123 122 Temperature (C.) FREE RISEFOAM Cream Time (s) 10-11 9 10 10 10 Gel time (s) 65 65 63 68 80 Risetime (s) 85 105 104 100 91 Mold fill time is the time when the foamstarts extruding through the mold vent holes. Temperature at mold fillis the temperature recorded in the core of the foam with a very thinthermocouple at the time when the mold is filled.

TABLE 2 PROPERTIES OF MOLDED FOAMS PRODUCED ACCORDING TO THEFORMULATIONS OF TABLE 1 Foam Number Ref A 1 2 3 4 40% IFD 244 247 303330 380 Core Density 34.7 33.7 35.0 35.4 36.9 25% CFD 3.5 3.4 4.3 4.95.4 50% CFD 5.2 5.2 6.5 7.5 9.0 65% CFD 8.4 8.7 11 12.5 15.9 Airflow 3.43.2 3.1 3.7 3.5

The results in Table 2 show that the addition of the PPDL2 polymerincreases the hardness of the foam as measured by CFD and IFD. It wasunexpected to observe this increase in hardness as diol (PPDL2) isreplacing the high functional polyol (NC 632). The substitution of partof the high functional polyol with the PPDL2 also need not decrease theairflow through the foam.

TABLE 3 PROPERTIES OF FREE RISE FOAM PREPARED ACCORDING TO THEFORMULATIONS OF TABLE 1 Foam Number Ref A 1 2 3 4 Core Density 28.3 28.729.3 29.4 31.8 50% CFD 3.4 4.0 4.5 4.8 6.3 Airflow 4.4 4.3 4.3 4.5 4.4

As observed for the molded foam, an unexpected increase in the hardnessof the foam was obtained upon substitution of PPDL2 for part of the highfunctional polyol.

EXAMPLES 5 TO 7

Machine molded foams were prepared at three different indexes using twodifferent levels of a copolymer polyol (NC 700) as control. The additionof copolymer polyol to flexible foam formulation is known to increasethe hardness of the foam. A portion of the high functional polyol wasthen replaced by PPDL2. The formulations are given in Table 4 and theproperties of the resulting molded foams are given in Table 5. For thecontrols, the results show that as the isocyanate index is increased,the hardness of the foam, as measured by CFD increases and the 75% HACSgets higher (worse). The same pattern is observed when an increase inthe amount of the copolymer polyol is added to the formulation showingthat the HACS are getting worse.

The substitution of part of the high functional polyol with the PPDL2polyol unexpectedly showed an increase in the foam hardness as measuredby 50% CFD and 40% IFD vs the foam based on 20 parts Specflex NC-700 andan improved 75% HACS vs the formulation based on 40 parts SpecflexNC-700 which has equivalent hardness. This improvement in the foamhardness and HACS is obtained without adversely affecting the otherproperties of the foam, including dynamic fatigue.

TABLE 4 REFERENCE FORMULATIONS FOR MOLDED AND FREE RISE FOAMS Examples*B C D E F G 5 6 7 NC632 80 80 80 60 60 60 72 72 72 NC700 20 20 20 40 4040 20 20 20 PPDL-2 diol 0 0 0 0 0 0 8 8 8 as dispersion CP 1421 0 0 0 00 0 0 0 0 T-80 40.3 44.8 47 40.3 44.8 47 40.3 44.8 47 Index 90 100 10591 101 106 90 100 105 Mold fill 44 36 37 37 35 35 46 44 47 time (s)Temperature 76 73 71 71 72 72 75 75 73 at fill (C.) Demold 4 4 4 4 4 4 44 4 time (min) Part weight 584 587 589 587 590 587 595 584 588 Molded37.1 37.3 37.4 37.3 37.5 37.4 37.8 37.1 37.3 density Time at 90 69 64 6273 60 59 72 66 68 deg C. (s) Demold 136 137 139 134 140 140 130 134 135temp (C.) Free Rise Foam Cream time 5 5 — 4 4 — 3 3 — Gel time s 61 60 —55 57 — 56 58 — Rise time s 120 131 — 103 107 — 91 104 — Free rise 2726.5 — 26.5 26.5 — 28.5 27 — density *Examples B-G are controls and arenot examples of the present invention.

TABLE 5 PHYSICAL PROPERTIES OF MACHINE MADE FOAMS USING THE FORMULATIONSGIVEN IN TABLE 4. Example* B C D E F G 5 6 7 PPDL diol 0 0 0 0 0 0 8 8 8(PHP) Iso index 90 100 105 91 101 106 91 101 106 NC-632 80 80 80 60 6060 72 72 72 NC-700 20 20 20 40 40 40 20 20 20 40% IFD 199 243 262 242286 302 223 267 300 (N) Core 36.0 36.0 36.1 36.3 35.6 35.1 36.6 36.337.2 Density 50% CFD 4.1 4.8 5.2 4.9 5.6 6.0 4.4 5.7 6.1 Airflow 2.3 2.42.7 1.7 2.3 2.2 2.0 2.4 2.4 Tensile str 131 147 143 184 181 178 149 155159 Elongation 116 116 100 120 110 99 122 103 99 Tear str 1.9 2.2 1.72.3 2.3 2.1 2.1 2.1 2.2 70% CS 9.0 8.3 7.7 10.3 8.6 8.1 10.0 8.7 8.9 75%17.2 27.1 25.2 25.8 38.0 41.5 17.9 23.2 23.7 HACS Peugeot fatigue testD42/1047 Height 2.7 2.5 2.4 3.1 2.6 1.6 2.7 2.8 loss (%) Load loss 14.412.8 12.8 13.0 12.5 12.0 11.8 14.7 (%) *Examples B-G are controls andare not examples of the present invention.

EXAMPLES 8 TO 11

Machine molded foams were prepared as per examples 1-4 wherein thefusible polymer PDDL3 was substituted for PPDL 2. The foam formulationsand the resulting properties of the foam are given in Table 6.

TABLE 6 FLEXIBLE FOAM FORMULATIONS USING PPDL3 Example 8 9 10 11 NC 63275 70 65 60 NC 700 20 20 20 20 PPDL triol 5 10 15 20 as dispersion CP1421 0 0 0 0 T-80 44.8 44.8 44.8 44.8 Part 332 334 325 333 weight 40%IFD 236 271 300 345 N Core 34.3 34.7 35.0 35.2 density (kg/m³) 25% CFD3.2 3.8 4.1 4.8 50% CFD 5.1 6.0 6.7 7.9 65% CFD 8.5 10.1 11.6 13.6Airflow 3.1 2.8 2.7 2.0 Resiliency 65.5 62.5 60.5 56.5 Tensile 130 136144 151 strength Elongation 86 83 86 76 Tear 2.3 2.5 2.6 2.8 strengthThese results show that the PPDL3 improves the hardness of the foamwithout having a negative affect on the other foam properties.

EXAMPLES H TO K

Examples H to K are comparative examples. Foams were made on the benchusing a dispersion of PCL (polycaprolactone diol 2,000 MW) in SpecflexNC-632 prepared as with examples 5-7. Formulations and foam physicalproperties are reported in table 7 showing that PCL did not give anyhardness increase.

TABLE 7 COMPARATIVE EXAMPLES OF FOAMS MADE WITH PCL Example H I J KNC-632 75 70 65 60 NC-700 20 20 20 20 PCL 5 10 15 20 CP-1421 0 0 0 0T-80 44.8 44.8 44.8 44.8 Demold time 5 5 5 5 (mm) Part weight 312 305317 293 (g) 40% IFD 218 203 205 204 Core density 34.1 33.1 32.9 33.7(kg/m3) 25% CFD 3.3 3.0 3.0 3.2 50% CFD 5.3 5.0 5.0 5.8 65% CFD 8.8 8.68.7 10.6 Airflow 3.4 3.3 2.5 3.3 Addition of PCL does not change foamhardness.

EXAMPLES 12 AND 13

Slabstock foams were made using either Dynacoll 7360 or Dynacoll 7381,dispersed in Voranol 3040 following the procedure of examples 5-7 and inthe following formulations:

TABLE 8 SLABSTOCK CONVENTIONAL FOAMS Example L 12 M 13 Voranol 3040 10082.9 100 80.2 Dynacoll 7360 15 Dynacoll 7381 15 Seed A 1.3 2.4Stabilizer A 2.4 Stabilizer B 0.8 Particle size 35 10 (microns) Bunheight (cm) 50 50 50 50 Core 160 160 160 160 temperature peak (deg C.)Core density 24.2 23.3 25.5 23.8 40% IFD 182 199 161 172 Airflow 2.6 2.54.3 4.3 Guide factor 7.5 8.5 6.3 7.2 Example L and M are comparativeexamples are not part of the present invention. Guide factor is theratio foam IFD/foam density. These data show the hardening effect ofboth Dynacoll's.

EXAMPLES 14 TO 16

Bench foams were made with a formulation containing no SAN copolymerpolyols as indicated below. The fusible polymer (b2) was introduced, at100 deg C., in melted form in the polyol premix kept at roomtemperature, just prior to adding the isocyanate.

TABLE 9 BENCH HR FOAMS WITH MELTED POLYMER Example N (comparative) 14 1516 NC-632 100 90 90 90 PPDL-2 10 Dynacoll 7380 10 Dynacoll 7381 10 Water3.7 3.7 3.7 3.7 DEQA 1.0 1.0 1.0 1.0 Niax A-1 0.05 0.05 0.05 0.05 Dabco33 LV 0.80 0.80 0.80 0.80 Tegostab B 0.8 0.8 0.8 0.8 8708 Dabco DC 0.20.2 0.2 0.2 5164 T-80 44.8 44.8 44.8 44.8 Part weight 318 320 317 326(g) 40% IFD 145 188 177 173 Airflow 5.1 4.5 4.3 4.2 These data confirmthe hardening effect of Dynacoll 7380 and Dynacoll 7381 which iscomparable to PPDL-2

EXAMPLE 17

Slabstock foams were made with Specflex NE-112 as isocyanate asindicated in Table 10 and using Dynacoll 7360 as load-bearing enhancerwhich had been dispersed in the polyol following the procedure used forexamples 5 to 7:

TABLE 10 Examples T 17 Voranol CP 6008 100 Speoflex NC-632 85 Dynacoll7360 15 Water 3.5 3.5 Niax A-1 0.05 0.05 Dabco 33 LV 0.25 0.25 TegostabB-8681 0.30 0.30 DEOA 0.75 0.75 Voranol 4053 4.0 4.0 Dabco T-9 0.15 0.15Specflex NE-112 67.8 67.8 Air addition in mix head Yes Yes Blow off time(s) 83 73 Core density (kg/m3) 34.8 37.7 40% IFD (N) 118 183 GuideFactor 3.4 4.8 Foam T is a reference and is not part of the invention.Example 17 shows that addition of Dynacoll 7360 to a MDI basedformulation gives a substantial increase in foam hardness.

Example 18

Slabstock foams were made with CO2 as an auxiliary blowing agent, asexplained in Table 11, using a Cardio equipment from Cannon:

TABLE 11 Example U V 18 Voranol CP 6008 100 70 Specflex NC-632 85Voralux HL 400 30 Dynacoll 7360 15 Voranol CP 1421 4.0 2.0 2.0 Water 3.72.7 2.7 Niax A-1 0.05 0.10 0.10 Dabco 33 LV 0.25 0.20 0.20 Tegostab B8681 0.30 0.30 0.30 DEOA 0.75 0.50 0.50 Dabco T-9 0.15 0.15 0.15 Air(liter/min) 2.5 16 24 CO2 (PHP) 0 2.8 2.8 Specflex NE-112 64 48.5 48.5Index 100 100 100 Core Density 33.5 26.7 32.7 40% IFD 95 68 88 GuideFactor 2.8 2.5 2.7 Airflow 4.9 6.3 4.8 Resiliency 57.5 53.5 53 75% CS3.8 4.0 3.7 Examples U and V are comparative examples and are not partof this invention.

Data in Table 11 demonstrate that the use of Dynacoll 7360 in a CO2blown slabstock foam, based on MDI, gives a foam harder than when usinga copolymer polyol, Voralux HL 400, and is comparable in terms ofphysical properties to a formulation containing a high water level,hence a large amount of MDI.

EXAMPLES 19 AND 20

Prepolymers of Dynacoll 7381 were prepared by reacting one mole of thispolyester with 2.1 moles of Isonate M-125 and 2.2 moles of a short MWdiol. In example 19 the diol was Voranol EP 2001, and in example 20, itwas Voranol P-1010. The reaction is carried out above the melting pointof Dynacoll 7381 or 85° C. for 3 hours under stirring and withoutcatalysis. Then Voranol CP 4702 is added to this prepolymer and thisblend is cooled down under stirring to disperse the reacted Dynacoll infine particles, with size below 5 microns. Two 17.2% by weightdispersions of such prepolymers, calculated on the total Dynacoll 7381and Isonate M-125 were foamed on the bench using formulation B and dataobtained are reported in Table 12:

TABLE 12 Example W 19 20 Specflex NC-632 41 33 33 Voranol CP-4702 39 2626 Specflex NC-700 20 20 20 Voranol EP-2001 0 13 Voranol P-1010 0 13Dynacoll 7381 + 0 8 8 Isonate M-125 Part weight (g) 341 335 335 40% IFD(N) 191 237 241 Core density 35.6 34.7 34.9 25% CFD 2.5 3.2 3.1 50% CFD4.4 5.2 5.4 65% CFD 8.0 9.0 9.4 Airflow 4.1 3.2 3.2 Resiliency 63.5 5758.5 Example W is a comparative example and is not part of thisinvention.

Data in Table 12 confirm that a prepolymer of Dynacoll 7381 givesincrease foam load bearing with good foam airflow.

EXAMPLE 21

Bench scale tests were done to determine the effect of replacing part ofa high functional polyol in a flexible foam formulation with Dynacoll7380. The foam formulations and the properties of the resulting aregiven in Table 13.

TABLE 13 INITIAL BENCH SCALE STUDY ON MOLDED FOAM Foam Number Ref X* RefY* 21 NC 632 80 72 72 NC 700 20 20 20 Dynacoll 7380 0 0 8 Fomrez 66-56 08 0 Index 100 100 100 Demold time (min) 4 4 4 (Part weight) 331 328 33540% IFD (N) 236 235 279 Core density 34.7 34.0 36.4 (kg/m³) 50% CFD 5.05.3 6.2 Airflow (CFM) 4.6 4.5 4.6 75% HACS 16.8 19.7 19.9 *Ref's X&Y arenot part of the present invention.

The results in Table 13 show that Fomrez 66-56, which has a chi factorat 300° K below 1.6, does not give any hardness increase, while Dynacoll7380, which has a chi factor of 2.79 at 300° K, shows higher foamload-bearing.

Other embodiments of the invention will be apparent to those skilled inthe art from a consideration of this specification or practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with the true scope and spiritof the invention being indicated by the following claims.

1. A process for the production of a polyurethane product by reaction ofa mixture of (a) at least one organic polyisocyanate with (b1) from 50to 99 percent by weight of at least one isocyanate-reactive materialhaving a functionality from 2 to 8 and a hydroxyl number of 20 to 140(b2) from 1 to 50 percent by weight of an isocyanate reactive fusiblepolymer substantially free of aromatic and having (1) a melting point ofbetween 45° C. and 180° C.; (2) a T_(g)/T_(m) of less than 0.65, asmeasured in ° K; and (3) a calculated composite interaction parameter(chi) of fusible polymer with other polyurethane components of less than2 at an absolute temperature of 400° K or a chi of greater than 1.6 at300° K., wherein the weight percent is based on the total amount of (b)and (b2) is either melted during the polyurethane production processthrough internal exotherm of the polyurethane reactions or is melted byexternal heating before or during the polyurethane reactions, and reactswith isocyanate, (c) optionally in the presence of a blowing agent and(d) optionally auxiliary agents known per se for the production ofpolyurethane foams.
 2. The process of claim 1 wherein theisocyanate-reactive composition is a polyether or polyester polyol or acombination thereof.
 3. The process of claim 1 wherein the fusiblepolymer is obtained by reacting an initiator with a lactone, omegahydroxy acid or ester wherein the lactone, omega hydroxy acid or esterhaving 7 to 20 carbon atoms in the ring or the chain.
 4. The process ofclaim 3 wherein the lactone, omega hydroxy acids or esters have 8 to 18carbon atoms in the ring or the chain.
 5. The process of claim 4 whereinthe lactone, omega hydroxy acid or ester have 9 to 16 carbon atoms inthe ring.
 6. The process of claim 3 wherein the initiator is apolyalcohol having 2 to 8 hydroxyl groups.
 7. The process of claim 6wherein the initiator is a polyalcohol having 2 to 4 hydroxyl groups. 8.The process of claim 3 wherein the hydroxyl equivalent weight of thefusible polymer is from 800 to 10,000.
 9. The process of claim 8 whereinthe hydroxyl equivalent weight of fusible polymer is 800 to 5,000. 10.The process of claim 1 for making a flexible foam wherein (b1) and (b2)are polyols having an average functionality of 2 to 4 and an averagehydroxyl number of 20 to
 100. 11. The process of claim 10 wherein wateris present in an amount from 0.5 to 10 parts by weight of (b).
 12. Theprocess of claim 11 wherein carbon dioxide is present as a gas or as aliquid to act as an auxiliary blowing agent.
 13. The process of claim 1wherein the polyisocyanate is toluene diisocyanate, polymethylenediisocyanate, isomers of diphenylmethylene diisocyanate or mixturesthereof.
 14. A flexible polyurethane product obtained from the processof claim
 13. 15. The flexible polyurethane product of claim 14 whereinthe product is in the form of a transportation vehicle seat.
 16. Theproduct of claim 15 wherein the seat is an automobile seat.